The proposed project aims at producing a comprehensive account of the developmental environment of disadvantaged children in order to identify those features of depriving environments that result in developmental retardation; designing intervention strategies for approximating developmentally normal environments for disadvantaged children at various ages from infancy through early school years and beyond; and evaluating the effects of developmentally normal environments, once produced, on the general developmental rates of children from previously depriving environments. Infants considered to be at risk of developmental retardation will be identified and intervention efforts will be made through a pediatrics clinic and home visits. Preschool day care programs will be continued and after-school day care programs established with the goal of training the children to initiate quality developmental interactions in other settings. Classroom organization and teaching procedures will be investigated for ways of increasing the amount and quality of developmental interactions occurring during the school day, and means of involving parents more directly in their children's learning activities will be pursued. The combined results of these intervention efforts will provide a system for prevention of developmental retardation through alteration of the child's environment.